Here’s a look at two of the end of the week movers in the biotechnology space – Adamas Pharmaceuticals, Inc. (NASDAQ:ADMS) and Vertex Pharmaceuticals Incorporated (NASDAQ:VRTX).

First up, then, Adamas. Over the last few days, many of the inputs that have driven volatility in the sector have been somewhat unusual – one-off, special situation type events. In this instance, however, we are back to standard biotechnology drivers. On Thursday, Adamas announced that the FDA had approved one of its lead development assets – a drug called GOCOVRI (amantadine) extended release capsules (previously ADS-5102) – in a target indication of dyskinesia in patients with Parkinson’s disease receiving levodopa-based therapy, with or without concomitant dopaminergic medications.

Chances are that most reading will be familiar with this indication, but for those that aren’t, dyskinesia is a sort of side effect of the standard of care treatment in the space (the above-mentioned levodopa) and is characterized by involuntary movements, twitching, that sort of thing. It’s more commonly associated with the period of time that physicians refer to as Off time in this population – that is, the time during which the levodopa isn’t having the desired effect.

The importance of this approval cannot really be understated. Dyskinesia is a very serious problem in the Parkinson’s population and this is the first and only drug the FDA has approved as a direct target asset for the condition.

Analysts have peak sales for the drug in excess of $1 billion meaning Adamas potentially has a blockbuster on its hands and, not surprisingly, markets are trading up on on the company considerably in the wake of the latest announcement. At close on Thursday, Adamas traded for $14.23 a share. The announcement came after hours and premarket activity on Friday has added more than 52% to this price, with the company set to open today at $21.75 a piece. Chances are, as standard participation ensues, that this appreciation will be added to throughout the session on Friday.

The other noteworthy mover as we head into the bell on Friday is Vertex. On Thursday, the company announced that the FDA has set a PDUFA date for one of its combination registration applications. The combination in question is tezacaftor/ivacaftor and is indicated as a potential therapy for people with cystic fibrosis (CF) ages 12 and older who have two copies of the F508del mutation or one F508del mutation and one residual function mutation that is responsive to tezacaftor/ivacaftor.

That is a pretty jargony indication description, and in many cases when we get a highly specific target population like this, the market potential for the drug on approval is somewhat limited. That’s not really the case here, however. The combination, if approved, will be meeting a large unmet need in a population of patients that have very few options right now (if any, in many cases) and there is a substantial boost in revenues on offer for Vertex if it can pick up a regulatory green light from the agency come PDUFA.

In cystic fibrosis, mutations make a massive difference as to what treatments work and what treatments don’t. By combining two of its lead CF assets, Vertex is hoping that it can expand the list of mutations against which its portfolio can be effective.

Latest data suggests there are more than 22,000 people ages 12 and older who have two copies of the F508del mutation, and there are more than 1,500 people ages 12 and older who have at least one residual function mutation that is responsive to tezacaftor/ivacaftor in vitro or in the clinic. This offers some degree of insight into the potential size of the target market and – for a combination that is likely going to cost in excess of triple digit thousands of dollars annually for patients, which is relatively standard pricing in this target indication – the degree of insight into the potential dollar revenue that Vertex stands to gain if and when the FDA gives the drug combination a thumbs up.

Chances are that markets will continue to load up on this one ahead of the decision date. The company gained a few percentage points in the wake of the announcement, which is pretty standard for a company of this size, but as we close in on PDUFA some speculative loading will likely boost Vertex further.

PDUFA is February 28, 2017.